Toggle Trigger

ABSTRACT

A trigger mechanism for a firearm which has a light trigger pull, reliably contains the high forces of the firing pin spring and achieves this with a mechanism which is simple and with few parts. A toggle linkage prevents the firing pin retainer releasing the firing pin whilst still allowing a light pull. It contains no internal sear and no pins within the toggle mechanism. It is adjustable for variations in manufacturing and can cater for various levels of trigger pull force. It realizes considerable economies for production, assembly and repair without sacrificing functionality.

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates to a trigger assembly for firearms including target rifles. The mechanism provides for a light trigger pull whilst greatly simplifying the mechanism.

Description of Prior Art

To enhance accuracy a great many shooters, desire the lightest trigger pull possible. However, the trigger must contain the high force of the firing pin spring to prevent inadvertent firing. Usually this force is contained by a sear type of arrangement. A sear may be described as a physical impasse being a block, other analytic or primitive shape or part, aligned with a mate to block movement until such time as it is moved. A trigger that is set too light or with too little sear engagement can have a tendency to go off prematurely. Containing the high force of the firing pin spring is thus at odds with the idea of a light trigger pull.

Referring to FIG. 1, a conventional trigger is in the cocked position. In this position a firing pin 13 is held back by a firing pin retainer 12. The firing pin retainer 12 is held in position by a trigger shoe 11. This is accomplished by the interaction of a sear shown in (A).

Referring to FIG. 2, the conventional trigger has been fired. Trigger shoe 11 is pulled and rotates around pin 14. This releases the sear and allows the firing pin retainer 12 to rotate around pin 15 releasing the firing pin 13 which moves forward and causes the firearm to fire.

The sear is under great load and thus these triggers have both a heavier than desirable pull and have lost motion or creep when in use. To reduce the effect of this load and reduce creep, the sear and its mate must be both precisely geometrically aligned to provide only an iota of engagement and are often highly polished, usually by hand, resulting in intricate and time-consuming work.

Other alternate designs are difficult, expensive and geometrically complex, with a relatively high number of moving parts and are therefore complicated to manufacture. They predominantly use a large number of pins within said mechanisms and the precise alignment thereof requires unnecessarily tight tolerances and are thus arduous to produce, assemble and repair.

BRIEF DESCRIPTION OF THE INVENTION

The invention overcomes these difficulties by being able to facilitate a light trigger pull, prevent premature firing, eliminate lost motion and significantly reduces excess complexities in manufacturing, the combination of these factors being the consummate goal of shooters and manufacturers. The trigger internal parts are contained between two outer sheets creating a chassis. The internal parts of the trigger consist of two toggles being a lower toggle, and a free-floating upper toggle.

Other parts are a trigger shoe, a torsion spring and a firing pin retainer. The invention does not rely on an internal sear nor any pins between the lower toggle, free-floating upper toggle and firing pin retainer. This is accomplished by having the lower toggle and free floating upper toggle aligned to create a geometrically rigid structure beneath the firing pin retainer. The combination of the lower toggle and free-floating upper toggle may also be described as the toggle linkage. This toggle linkage rests upon a trigger shoe with an adjustable screw at a point along its length. The trigger shoe and adjustable screw provide a stop for the toggle linkage. A torsion spring provides a pre-load to keep the toggle linkage against the adjustable screw of the trigger shoe and also provides a force to reset the mechanism for the next cycle.

When the trigger shoe is pulled it rotates and causes the adjustable screw to push the toggle linkage beyond its tipping point. At this stage the force of the firing pin spring via the firing pin which itself is pushing on the firing pin retainer causes the toggle linkage to collapse. This allows the firing pin retainer to release the firing pin and the firing pin moves forwards to fire the firearm.

When the trigger shoe is released and the firing pin is moved rearwards during reloading of the firearm, the torsion spring resets the lower toggle, the upper free-floating toggle and the firing pin retainer to their original positions ready for the next cycle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side detail view of a conventional trigger in the cocked state as prior art.

FIG. 2 is a side detail view of a conventional trigger in the fired state as prior art.

FIG. 3 is a perspective view of the new invention showing external parts.

FIG. 4 is a side detail view of the new invention showing internal parts.

FIG. 5 is a side detail view of the new invention showing pins and screws.

FIG. 6 is a side detail view of the new invention showing critical internal parts when in the cocked position.

FIG. 7 is a side detail view of the new invention showing critical internal parts at the tipping point.

FIG. 8 is a side detail view of the new invention showing critical internal parts in the fired and collapsed Toggle Linkage state. p FIG. 9 is a side detail view of a modified form of the new invention showing internal parts in the cocked state with the torsion spring inverted.

FIG. 10 is a side detail view of the new invention showing parts which make up the Toggle Linkage.

DETAILED DESCRIPTION OF THE INVENTION

With regards to firearms, the invention is able to facilitate a light trigger pull, prevent premature firing and importantly, significantly reduce excess complexity in manufacturing assembly and repair. Throughout this description the term forward, forwards, front or fore shall refer to the orientation of the firearm and trigger towards the direction of the barrel of the firearm. Throughout this description the term rearward, rearwards, rear or aft shall refer to the orientation of the firearm and trigger towards the direction of the butt of the firearm.

With reference to FIG. 3 the trigger assembly is held to the firearm either directly, by an adapter, by a hanger or other necessary device via the Locating Pin Fore 61 and the Locating Pin Rear 62. The trigger internal parts are captured within an external chassis being the Left Sheet Chassis 31 and the Right Sheet Chassis 32 which can be made of metal sheet or other suitable material. Undertravel Screw 33 is located in Left Sheet Chassis and Overtravel Screw 34 is located in Right Sheet Chassis.

With reference to FIG. 5 Left Sheet Chassis and Right Sheet Chassis are both aligned and spaced by screws being Sheet Connecting Screw A 63, Sheet Connecting Screw B 64, Sheet Connecting Screw C 65 and Sheet Connecting Screw D 66.

With reference to FIG. 4 internal parts of the trigger comprise of Trigger Shoe 44, Lower Toggle 45, Upper Free-Floating Toggle 46 and Firing Pin Retainer 47. These parts may be made from steel plate or other suitable material. Additional internal parts are Torsion Spring Upright 48, Trigger Shoe Adjustment Screw 49, Firing Pin Retainer Adjustment Screw 50. Trigger Shoe Adjustment Screw is located in Trigger Shoe, proximate as shown. Firing Pin Retainer Adjustment Screw is located in Firing Pin Retainer, proximate as shown. Torsion Spring Upright is centered on Sheet Connecting Screw A with one arm grounded on Sheet Connecting Screw B and the other arm acting upon Lower Toggle. Firing Pin Retainer is held in position by and free to rotate about Locating Pin Fore.

With reference to FIG. 10 the combination of Lower Toggle and Upper Free-Floating Toggle may be alternatively referred to as the Toggle Linkage.

With reference to FIG. 5 Lower Toggle is held in position by and free to rotate about Lower Toggle Screw 67. Trigger Shoe is held in position by and free to rotate about Trigger Shoe Screw 68.

With reference to FIG. 6 critical internal parts are shown with the trigger in a cocked state. In this state the Trigger Shoe is at rest at its Starting Position D and the Firing Pin 71 is being prevented from moving forwards to fire the firearm by the Firing Pin Retainer. Tipping Line C is indicated by a straight dotted line and is the line between each end of the Toggle Linkage. In this position the Lower Toggle and the Upper Free-Floating Toggle are aligned such that they have bias rearwards of the Tipping Line. Upper Free-Floating Toggle is recessed within and completely self-constrained between the Firing Pin Retainer and the Lower Toggle. The downwards force of the Firing Pin acting through the Firing Pin Retainer, the Upper Free-Floating Toggle and the Lower Toggle keeps the Upper Free-Floating Toggle and the Lower Toggle in this rearward bias of the Tipping Line and thus in their locked position. This alignment is held in place by the Trigger Shoe Alignment Screw via the Trigger Shoe and acts as a stop to prevent the Lower Toggle from moving further rearwards. In this position with rearward bias of the Tipping Line the Lower Toggle and the Upper Free-Floating Toggle form a rigid structure which prevents the Firing Pin Retainer from rotating downwards and releasing the Firing Pin. FIG. 6-8 are now a progression of pulling the Trigger Shoe.

With reference to FIG. 7 the Trigger Shoe has been moved rearwards to position E which is equivalent to a person pulling the trigger in use. This causes Trigger Shoe Adjustment Screw to move Lower Toggle and Upper Free-Floating Toggle forwards. The alignment of Lower Toggle and Upper Free-Floating Toggle is now forwards beyond the Tipping Line C. At this point there is no more rigidity in the Lower Toggle and Upper Free-Floating Toggle linkage and thus the toggle linkage starts to collapse under the downwards force of the Firing Pin and Firing Pin Retainer.

Note that the ends of the Upper Free-Floating Toggle are pointed, nearly pointed or slightly radiused thus reducing bearing force to minimal levels. Note also that the Torsion Spring Upright is acting on the Lower Toggle close to the Lower Toggle Screw and thus has a low leverage force. This means that even though the Lower Toggle and Upper Free-Floating Toggle linkage was quite rigid in FIG. 6, the force necessary to move the Lower Toggle and Upper Free-Floating Toggle linkage beyond the Tipping Line by the Trigger Shoe and Trigger Shoe Adjusting Screw to the position in FIG. 7 was very light. In this way the large forces of the Firing Pin are contained while still maintaining a light trigger pull and preventing premature firing.

With reference to FIG. 8 the Lower Toggle and Upper Free-Floating Toggle linkage has completely collapsed and moved forwards. The magnitude of this motion is limited by Sheet Connecting Screw A. The Upper Free-Floating Toggle is still completely self-constrained between Lower Toggle and Firing Pin Retainer throughout its entire range of movement. This allows the Firing Pin Retainer to rotate downwards and release the Firing Pin. The Firing Pin is then free to move forwards to fire the firearm.

With reference to FIG. 8 the trigger is now in a fired state. In this state the Torsion Spring Upright places a rearwards force on Lower Toggle. When finger pressure is released from the Trigger Shoe and the Firing Pin is moved rearwards in the course of reloading the firearm, the force from Torsion Spring Upright causes Lower Toggle, Upper Free-Floating Toggle and Firing Pin Retainer to move back to the cocked position per FIG. 6. The cycle is then ready to be repeated.

With reference to FIG. 9 in a modified form the Torsion Spring Upright may be replaced by Torsion Spring Inverted 81. Inverting the position of the Torsion Spring results in spring force being applied closer to the center of the Toggle Linkage and thus with greater leverage and therefore force. In this configuration the Torsion Spring Inverted is centered on Sheet Connecting Screw B and grounded on Sheet Connecting Screw A. As some shooters require or desire a heavier trigger pull this can be accomplished in this fashion. By arranging the Torsion Spring in such a fashion, the simplicity of design and use of only one spring is maintained.

Undertravel Screw can be adjusted to set Trigger Shoe in the correct position while the trigger is on a cocked or ready to fire condition. This adjustment allows for broader manufacturing tolerances and for wear.

Overtravel Screw can be adjusted to limit the travel of Trigger Shoe too much beyond that necessary for Lower Toggle and Upper Free-Floating Toggle to go beyond the Tipping Line, that point at which the Toggle Linkage collapses and the Firing Pin fires the firearm. This adjustment allows for broader manufacturing tolerances and for wear.

Trigger Shoe Adjustment Screw can be adjusted to control the position of the Lower Toggle and Upper Free-Floating Toggle versus the Tipping Line. With Trigger Shoe adjusted to the desired position when the trigger is in the cocked or ready to fire condition by Undertravel Screw, the Trigger Shoe Adjustment Screw can then be adjusted forwards until the Tipping Line is exceeded, Toggle Linkage collapses and the Firing Pin moves forwards. The Trigger Shoe Adjustment Screw can then be finely adjusted rearwards to the point where the Toggle Linkage and Firing Pin Retainer just holds the Firing Pin in the cocked position. The Trigger Shoe Adjustment Screw may then be screwed further rearwards from this point to increase the rearwards bias of the Toggle Linkage, enhance the rigidity of the Toggle Linkage in the cocked position and thus prevent premature firing. Important is that in this cocked position the Toggle Linkage rests against the Trigger Shoe Adjustment Screw which therefore also acts as the rearward mechanical stop for the Toggle Linkage. Thus, the Trigger Shoe Adjustment Screw acts in direct mechanical communication between Trigger Shoe and Toggle Linkage. This mechanical train of Trigger Shoe to Trigger Shoe Adjustment Screw to Toggle linkage being that which will ultimately fire the firearm. Thus, being imbedded directly in this train, when adjusted, Trigger Shoe Adjustment Screw acts directly and without any intermediary upon and within this train. Being imbedded in this way, any adjustment made to Trigger Shoe Adjustment Screw, directly controls both the rearwards bias of the Toggle linkage to control premature firing whilst also completely avoiding any introduction of any lost motion of the Trigger Shoe when the trigger is being used. This ease and singularity of adjustment within the invention greatly enhances functionality and usability. Furthermore, this adjustment also allows for broader manufacturing tolerances and allows for wear.

Firing Pin Retainer Adjustment Screw can be adjusted for dimensional variations in Lower Toggle and Upper Free-Floating Toggle part sizes. In this case the Firing Pin Retainer Adjustment Screw can be adjusted to remove unnecessary free-play within this linkage and thus this adjustment also allows for broader manufacturing tolerances and for wear.

Note that in this invention all these adjustments are arranged so that they may be made from underneath the trigger and thus with the trigger still in situ in the firearm.

Note that there are no pins located between the Lower Toggle, Upper Free-Floating Toggle or Firing Pin Retainer. Whereas pins require precise alignment and therefore tight manufacturing tolerances of components in two, if not three dimensions to achieve fit between parts or within mechanical part trains, inventing a design which has a fully self-constrained Upper Free-Floating Toggle, free of pins, coupled with the ability to easily adjust the Toggle Linkage removes the necessity of tight manufacturing tolerances thus greatly easing production, assembly and repair. This adds to the novelty of the invention.

Note that solely using a Lower Toggle and Upper Free-Floating Toggle to lock the Firing Pin Retainer in place means that no internal sear is necessary in this invention. This removes geometric complexity of design, eases manufacturing tolerances and negates the necessity of hand polishing a sear and its mate to reduce trigger pull weight negating arduous, intricate and time-consuming work. This adds to the novelty of the invention.

Note that the parts of this invention are uniquely designed such that Side Sheets are able to be profile cut from sheet and internal parts are able to be profile cut from plate. Coupled with the aforementioned ability within the invention for inherent adjustments due to manufacturing variations to be made, profile cutting such as this versus intricate machining of parts, as is common in contemporary triggers, greatly simplifies and speeds manufacturing and this adds to the novelty of the invention. 

I claim:
 1. A trigger assembly for use with firearms comprising: a) Two sheets of material which act as an external chassis for internal parts; b) A lower toggle which is pivotally attached to said sheet chassis; c) A firing pin retainer which is pivotally attached to said sheet chassis; d) An upper toggle being free floating and self-constrained between said lower toggle and said firing pin retainer with said upper toggle having pointed, near pointed or slightly radiused ends; e) A toggle linkage being the combination of said lower toggle and upper toggle; f) A geometric tipping line being a straight line between each end of said toggle linkage; g) Said toggle linkage being a rigid set when arranged ante said tipping line; h) A trigger shoe which is pivotally attached to said sheet chassis; i) A trigger shoe adjustment screw attached to said trigger shoe; j) Said trigger shoe adjustment screw being in operational communication with said toggle linkage; k) A torsion spring being grounded at one end with the other end applying force to said toggle linkage; l) Whereby when said trigger shoe is pulled causing said trigger shoe adjustment screw to move said toggle linkage forward and collapse said toggle linkage as toggle linkage is moved post said tipping line; m) Whereby when said toggle linkage collapses said firing pin retainer rotates downward releasing firing pin and firing the firearm; n) Whereby said trigger shoe adjustment screw may be adjusted to control bias between said toggle linkage and said tipping line; o) Whereby adjustment of said trigger shoe adjustment screw introduces no lost motion. 2) The trigger assembly in accordance with claim 1 further comprising of an overtravel adjustment screw for said trigger shoe. 3) The trigger assembly in accordance with claim 1 further comprising of an undertravel adjustment screw for said trigger shoe. 4) The trigger assembly in accordance with claim 1 further comprising of a firing pin retainer adjustment screw for adjustment of free-play in said toggle linkage. 5) The trigger assembly in accordance with claim 1 in modified form comprising said torsion spring installed in an inverted position to increase force of trigger pull. 6) The trigger assembly in accordance with claim 1 wherein the external chassis sheet may be profile cut from sheet material; 7) The trigger assembly in accordance with claim 1 wherein internal parts being said lower toggle said upper toggle said trigger shoe and said firing pin retainer may be profile cut from plate material; 8) The trigger shoe adjustment screw of claim 1 being able to be adjusted from beneath with the trigger in situ in the firearm; 9) The adjustment screw of claim 2 being able to be adjusted from beneath with the trigger in situ in the firearm; 10)The adjustment screw of claim 3 being able to be adjusted from beneath with the trigger in situ in the firearm; 11)The adjustment screw of claim 4 being able to be adjusted from beneath with the trigger in situ in the firearm. 